Double carbonylation reaction of benzyl halides using a cobalt carbonyl catalyst has previously been known as a method of producing 2-oxo-3-aromatic carboxylic acid derivatives. This reaction, however, gives a low yield and selectivity and requires limited starting materials. Accordingly, it cannot always give 2-oxo-3-aromatic carboxylic acid derivatives having the desired substituents [see, for example, M. Foa and F. Francalanci, J. Mol. Cat., 41, 89 (1987)].
It is known on the other hand that 2-oxo-3-aromatic butanoic acid esters are obtained by ring-opening isomerization reaction of .beta.-aryl-.beta.-methylglycidic acid esters with acid catalysts. This method cannot give other carboxylic acid derivatives. Moreover, depending upon an acid catalyst used, the yield and selectivity are both low (see, for example, Japanese Patent Publications Nos. 35068/1978 and 35069/1978 and Japanese Laid-Open Patent Publications Nos. 149970/1978 and 99445/1981).
Rearrangement reaction of .alpha.,.beta.-dialkyl-.beta.-aromatic glycidic acid esters with acids is known as a method of producing 2-oxo-3-aromatic carboxylic acid derivatives having two substituents at the 3-position [for example, see J. Am. Chem. Soc., 9-,8 4581 (1976) and J. Org. Chem., 40, 1741 (1975)]. However, this method is only known for the synthesis of compounds having limited substituents. Moreover, depending upon the acid catalyst used, the yield and selectivity are very low, and the method cannot be said to be a commercially efficient method.
A method of producing 3-(3',4'-dimethoxyphenyl)-3-methyl-2-butanone by oxidation with selenium and a method of producing 2-cyano-3,3-disubstituted carboxylic acid derivatives by autoxidation are also known [see Acta Pharm. Suec., 13, 65 (1976) and J. Org. Chem., 35, 3240 (1970)]. These methods, however are limited in respect of substituents, and the yields are low. Hence, they cannot be said to be general commercial manufacturing methods.
Thus, by the conventional processes, 2-oxo-3-aromatic carboxylic acid derivatives having the desired substituent at the 3-position cannot be produced conveniently with simplicity in good yields. It is an object of this invention to provide a commercially effective process for producing 2-oxo-3-aromatic carboxylic acid derivatives which are important synthetic intermediates for the production of medicines and agricultural chemicals.